The invention relates to rotary apparatus for performing a variety of functions on a moving workpiece. The workpiece may be a continuous strip, or may be a series of separate strips, which move continuously through the rotary apparatus. The material in many cases will be strip steel, but the invention is of much wider application.
Rotary apparatus for performing a variety of functions on continuous strip material such as strip steel, have been proposed over the last at least fifty years. However, a need has remained for a rotary apparatus to satisfactorily perform precise functions on a moving strip. There are necessarily upper and lower rotary devices which register with one another and they carry respective upper and lower rotary dies. It is well known in all die forming operations that the two dies must register precisely with one another on opposite sides of the workpiece before they close. It is for this that most of the earlier proposals have not been successful. No way was known to achieve a satisfactory form of precise registration of each pair of dies.
However, in U.S. Pat. No. 5,040,397 of Ernest R. Bodnar, Rotary Apparatus granted Aug. 20, 1991, there is shown a form of rotary apparatus, in which upper and lower rotary devices carried semi-rotary die carriers. The die carriers were themselves guided by guide pins. The guide pins rode in cam tracks. The guide pins were located in pairs, one at each end, of each of the semi-rotary devices, and the guide cams were located at opposite ends of the rotary devices.
By offsetting one of the guide pins at one end relative to the guide pin at the other end, and also by precisely profiling the guide cams at each end of each of the rotary devices, it was possible to bring the semi-rotary die supports into precise registration just prior to closing, and during closing, and just after closing on the workpiece. This proposal has proved to be satisfactory for many applications. An improvement to the above described apparatus of U.S. Pat. No. 5,040,397 is described in Canadian Patent Application No. 2,066,803. In that patent application, the inventor, Ernest R. Bodnar, describes the provision of guide pins on each of the semi-rotary die supports. By offsetting respective forward and rearward guide pins on respective guide supports, and by providing two separate guide cams at each end of the rotary apparatus, it then became possible to provide for all four pins to engage respective guide cams just prior to closing, during closing, and just after closing. This proposal may produce a much improved degree of registration between the respective dies carried on the die support. This is particularly important in heavier duty applications, or in applications where the line speed was desired to be increased. Even in this system however there were limitations. For example, it will be understood from a simple geometrical analysis that whereas two dies may register with one another just prior to closing, and during closing and after closing, they are in fact traversing arcs of a circle, as the rotary supports rotate.
This means that the linear speed of the die was greatest at the point where the two dies closed, and was somewhat reduced just prior to closing and just after closing.
On the other hand, since the dies are required to perform operations on a flat workpiece, whether a continuous strip, or discontinuous strip pieces, it will be apparent that there is a very slight degree of xe2x80x9cmismatchxe2x80x9d in speed of forward movement as between the pair of dies, and the workpiece between them just before closing and just after closing. Precise speed matching is achieved only at the point where the dies are fully closed on the workpiece and the planes of the two dies are precisely tangential to each other.
In operations where relatively thin workpieces were being treated, or where relatively shallow formations were being formed, this slight degree of mismatch in speed did not produce any serious consequences. However, it is desirable to apply this technology to a wider range of products. It is desirable to apply this technology to products having a greater physical thickness than relatively thin sheet metal workpieces, and it is also desirable to apply this technology to the drawing of deeper formations in the workpiece.
In both of these cases, it is apparent that the contact time period during which the two dies are in contact with the workpiece will be somewhat increased as compared to working on thin sheet workpieces such as thin sheet metal and/or drawing relatively shallow formations. In these cases, any degree of mismatch in linear speed between the workpiece itself, and the two dies becomes much more significant.
Accordingly, it is desirable to provide in the first place a method of accommodating the mismatch in speed occurring between the dies moving around a rotary arc, and the workpiece moving along a linear path.
A further problem however relates to the design of the rotary apparatus itself.
In the above noted U.S. patent, and the development thereof described above, herein termed the xe2x80x9ctwo pin rotaryxe2x80x9d, and the xe2x80x9cfour pin rotaryxe2x80x9d respectively, the circumferential path around which the die itself could pass was determined by the circumferential path around which the semi-rotary die supports themselves could pass. This meant that if it was desired to increase the size and particularly the depth, of the dies, the entire design of the rotary apparatus had to be redesigned to accommodate these variations.
This clearly either limited the degree of application of the rotary apparatus or meant that considerable engineering costs were incurred each time the rotary apparatus was designed to handle a particular size and depth of die.
Clearly, it is desirable for a more or less standard size of rotary apparatus to be arranged so as to accommodate dies which are themselves of different sizes and in particular in which the dies are of different depths, without being obliged to re-engineer the entire rotary apparatus itself desirably, all that will be required is to place the rotary support devices on centres which are further apart for deeper dies or closer together for shallower dies, and of course, to alter the size and pitch of the gears which interconnect them to ensure that they rotate in unison. This itself is a relatively much simpler task than re-engineering the whole of each pair of the rotary devices themselves.
For the purposes of this application, the term xe2x80x9cformingxe2x80x9d is deemed to incorporate by reference any die operation which may be performed on a workpiece, whether it may be termed in the trade as xe2x80x9cembossingxe2x80x9d xe2x80x9cformingxe2x80x9d xe2x80x9cdrawingxe2x80x9d xe2x80x9cblankingxe2x80x9d xe2x80x9ccuttingxe2x80x9d, or any other operation on a workpiece which is performed by a pair of dies, and wherever used herein the term forming is deemed to incorporate any and all such operations, including those not specifically mentioned above.
According to the invention, there is provided a rotary apparatus for continuous rotary forming of web workpiece, the apparatus comprising a rotatable first roll unit and corresponding rotatable second roll unit; a first die support member carried by the first roll unit, the first die support member having a leading edge and a trailing edge respective to rotation of the first roll unit; a second die support member carried by the second roll member, the second die support member having a leading edge and a trailing edge respective to rotation of the second roll unit; means for transporting a web workpiece in a forming plane between said first and second roll units;
each die support member comprising a first part carried by the respective roll unit and including the leading and trailing edge and a second part having a platen surface for mounting a die, the second part being mounted on the first part for reciprocal motion transverse to the leading and trailing edges.
Each first and second die support member may be rotatably received in a longitudinal recess of its respective roll unit, the recess having a concave arcuate bearing surface a complementary to a convex arcuate surface of the first part of the respective die support member, the recess defining a concave section of a cylinder and the first part of the respective die support member defining a complementary convex section of said cylinder. The respective concave and convex sections of said cylinder may be minor sections.
Preferably, the first part of each first and second die support member and the second part of the first and second die support members are connected for reciprocal movement with respect to each other through resilient connecting members. Each resilient connecting member may be formed of polyurethane rubber and may be seated in seating recesses in both of the first and second parts. Stop members may be provided to limit the reciprocal motion on one of the first and second parts.
Rotation of the first part of the die support member in the recess is controlled by cam means which may include a cam follower on at least one end of the die support member in the region of the leading edge engaging a continuous cam. Suitably the cam means also includes a cam follower on the other end of the die support member in the region of its trailing edge and engaging a continuous cam.
Alternatively the cam means may comprise a four pin system including a cam follower on one end of a die support member in the region of a leading edge and engaging a continuous cam, a cam follower on the other end of said die support member in the region of the leading edge and engaging a discontinuous cam, a cam follower on said one end of the die support member in the region of the trailing edge and engaging a discontinuous cam, and a cam follower on the other end of said die support member and engaging a continuous cam.
According to the invention there is also provided a rotary apparatus for rotary forming of a web workpiece which apparatus comprises: a rotatable first roll unit and corresponding rotatable second roll unit, said units being connected for synchronous rotation through rotary cycles, each of said units comprising a carrier having a central axis for rotation thereabout; means for transporting a web workpiece between said units in a forming plane at a web speed; means for rotating the first and second roll units at constant opposite rotational speed to have a roll unit tangential peripheral speed at the forming plane similar to the web speed; each roll unit being provided with at least one recess defining a concave minor section of a cylinder having a longitudinal axis parallel with said carrier central axis; a die support member having a leading edge and a trailing edge being rotatably received within said recess, the die support member including a first part having a curved convex surface nested in said recess and defining a similar minor section of said cylinder, the die support member also including a second part projecting out of said recess and said die support member being rotatable about the notional central axis of said cylinder and offset from the first part of the die support member. The first part and the second part of each die support member may be separate one from the other and connectable one to the other.
The cam means, as in the previous alternative, may comprise a cam follower on at least one end of the die support member in the region of the leading edge engaging a continuous cam. Again, suitably, the cam means includes a cam follower on the other end of the die support member in the region of its trailing edge and engaging a continuous cam.
As before, the cam means may be a four pin system including a cam follower on one end of a die support member in the region of a leading edge and engaging a continuous cam, a cam follower on the other end of said die support member in the region of the leading edge and engaging a discontinuous cam, a cam follower on said one end of the die support member in the region of the trailing edge and engaging a discontinuous cam, and a cam follower on the other end of said die support member and engaging a continuous cam.
The cam follower in the region of the leading edge and the cam follower in the region of the trailing edge may be located on end extensions of the die support member, the extensions extending out of the recess and respectively flush with ends of the second part of the die support member. The axles of the die support member may also be located on the extensions. Such a system may provide substantial versatility. For example it may be possible to interchange dies of different depths on the die support member.
Each roll unit may suitably include four die support members.
Bearing arms may provided for said axles of each die support member, the bearing arms being rotatable on the carrier central axis.
The invention further comprises a rotary apparatus wherein a cut to length mechanism is provided upstream of the rotary forming apparatus, whereby the workpiece may be cut into separate plates or pieces, which are then passed successively through the rotary apparatus, in timed relation to the formation of openings, or other formations therein by the rotary apparatus.
The invention further comprises such a rotary apparatus, wherein provision may be made for separating one of the rotary units from the other in a pair of rotary units, so that a portion of workpiece may pass therethrough untreated while maintaining the rotation of said moved rotary unit, whereby to maintain the rotation of the two rotary units in timed relation continuously.
The various features of novelty which characterize the invention are pointed out with more particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.